Mehtod of plating ferrous metals.



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names or PLATING reasons METALS.

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Ito Drawing.

To all whom it may concern Be it known that I, WILLIAM E. WATKINS, a. citizen of the United States of America, residing at the city of New York, county of New York, State of New York, have invented certain new and useful Improvements in Methods of Plating Ferrous Metals, of which the followin'g is a specification. v My invention relates to the plating of one metal, such as iron, or steel with another, such as tin, and consists, broadly stated, in the employment of a finely ground oxid or salt of tin to form a coating for the ferrous metal and then subjecting the metal, so

coated, to a temperature at or above the- -\melting point ofthe plating metal and sumcient. to raise the ferrous metal to approximately its welding heat. As a result the o'xid or salt, whichever is used, is reduced of the metallic base thereof is deposited on the surface of the ferrous metal in a molecular union 'therewith,fwhile an exterior layer containing a magnetic oxid of iron is formed on the plating metal which protects the same from oxidation during the cooling of the plated article. I do not herein claim the product of the process described as said product is described and claimed in my a lication filed November 18, 1914, Serial 0. 872,835. D As an example of the best method at present known to me for carrying out my improved process, I would proceed as follows: I first grind a quantity of oxid of tin, or of one of the salts of tin, such. as chloridof tin to great fineness in a suitable inert, viscous, volatile vehicle such as a mixture of equal parts of Mexican'crude oil and an 40 American fuel oil. In practice I am using about 440 pounds of every 8 gallons, or approximately 64: pounds of the oil mixture, but these proportions may be varied to produce plating films of different thicknesses. I then apply this viscous mass in an even, dense coating to the ferrous metal to be plated. In the case of sheets I pass the same through rolls which are coated with the plating material. Such plating material can also be applied, though less advantageously, by brushing or pouring it on, or by dipping the article in a plastic mass of the oil and chlorid mixture. The sheet or article so coated is then passed into or through a lfurnace in which the tin oxid or salt for Specification of Letters lPatent. Pattemfl tgdl F gb, 12 1918 Application filed November 11, me. Serial Ito. 871,583.

a temperature at or above the melting point of tin is maintained. The melting point of tin is comparatively low, and in order to raise the ferrous metal to a temperature at which a molecular union between the ferrous metal and the fused plating metal may be created, and also to start the reduction of theoxid or salt, it is obvious that a higher temperature must be maintained in the furnace.-

The furnace'temperature required would depend in part on the length of time during which the ferrous metal is to be retained in the furnace. If the coated ferrous sheets or other articles are passed quickly through the furnace, a very high heat is'needed to bring the ferrous metal up to the necessary temperature in the short period of exposure to such heat. If they are allowed to remain longer in the furnace, a lower temperature will serve the purpose. I find that with a furnacetemperature of 2200 Fahrenheit or somewhat less, the operation can be carried on, very rapidly. In a few seconds the heat of the furnace will bring the surfaces of a sheet of steel of about No. 28 gage up to the necessary temperature and institute and complete a reaction which results in the reduction to metallic tin of the oxid or salt, whichever is used, and deposit the same on the ferrous metal in a uniform film or layer of pure tin which is molecularl united to the ferrous metal. An exterior layer containing magnetic oxid of iron is formed on and covers the tin film, protecting it from any oxidation which might otherwise occur while the article is being withdrawn from the furnace and cooling. This outer layer can be subsequently removed in any convenient manner, as by an acid bath.

The final result of the above described process is a sheet or other article havinga core or base of iron or steel and an exterior of pure tin molecularly deposited onto the iron so evenly and closely that it cannot be scaled or cracked off either by mechanical action or by uneven. expansion or contraction.

While I have mentioned chlorid of tin, other salts might be employed, and other volatile "vehicles substituted for the oil mentioned.

Having therefore described my invention, I claim:

, 1. The method of plating ferrousmetals which consists in subjecting the same, while tin and suflicient 1.25am j which consistsin'subgecting the same, while in surface contact'with a compound of tin to a temperature above the melting point of tin and suflicient to" raise the ferrous metal approximately to a welding heat thereby converting the tin compound into tin in the shape-of a substantially continuous plating layer molecularly deposited on the metal.

3; The methodof plating ferrous metals which consists in sub ecting the same, while in surface contact with a compound of tin to a temperature above the melting point of.

approximately to a welding heat thereby converting the tin com ound into tin in the shape of a substantial y continuous plating layer molecularly deposited on the ferrous metal and forming an exterior adherentlayer containing magneticoxid of iron.

4. The method of platmg ferrous metals which consists in sub ecting the same, while to raise the ferrous metal in surface contact with a compound-of l to a temperature above the melting point of tin and suflicient to raise the ferrous metal approximately to a welding. heat thereby.

converting the tin comfiound into tin in the shape of a substantia y continuous plating layer molecularly de osited on the ferrous metal, forming an exterior adherent layer containing magnetic oxid of iron and;-

finally removing said exterior layer.

5. The method of which consists in sub ecting the same while coated with an even layer of;.a mixture of a finely divided oxid of tin in a viscous volatile vehicle to a temperature above the melting point of tin and suflicient to raise the ferrous metal approximately to a welding heat thereby converting the tin oxid into tin in the shape of a substantially continuous plating layer molecularly deposited on the plating ferrous metalsferrous metal, forming an exterior layer con- I taimng magnetic OXld of iron and finally removmg said exterior'layer.

' WILLIAM E. WATKINS.

Witnesses:

A.- Panxnn SMITH,

M. G. CRAWFORD. 

